Electric timekeeper



April 21, 1964 HIDEAKI YASUKAWA 3,129,554

ELECTRIC TIMEKEEPER Filed Aug. 27, 1962 2 Sheets-Sheet 1 Prior Ari April21, 1964' HIDEAKI YASUKAWA 3,129,554

ELECTRIC TIMEKEEPER Filed Aug. 27, 1 962 2 Sheets-Sheet 2 11 fie UnitedStates Patent Ofitice 3,129,554 Patented Apr. 21, 1964 3,129,554ELECTRIC TIMEKEEPER Hideaki Yasukawa, Suwa-shi, Nagano-ken, Japan, as-

signor to Kabushiki Kaisha Suwa Seikosha, Suwa-shr,

Nagano-ken, Japan, a joint-stock company of Japan Filed Feb. 27, 1962,Ser. No. 176,069 Claims priority, application Japan Mar. 6, 1961 4Claims. ((11. 58-23) This invention relates to electric timekeepers, andmore particularly it relates to an improvement in electric timekeeperswhereby inconveniences, defective operation, and breakage at the time ofsetting of the timekeeper indicating hands are effectively prevented.

More specifically, this invention relates to battery-powered timekeepers(particularly battery-powered watches and clocks) of the type wherein adriving pawl is fixed by way of a spring material to an oscillatingmember which is driven (excited) electrically, and the driving pawl,which oscillates together with the oscillating member and undergoesreciprocating motion, imparts rotation in one direction to a ratchetwheel, whereby the indication mechanism (or mechanism operating the timeindicating hands) is driven.

Electric timekeepers of this type are capable of driving, with highefficiency, the indication mechanism by means of the oscillating memberwhich oscillates at a constant frequency to become the time standard ofthe tirnekeeper. Accordingly, this type of electric timekeeper has beenutilized widely for known kinds of hanging clocks and also for recentwatches.

However, if, at the time of setting the timekeeper hands, the frictionstop of the center wheel shaft and the cannon pinion (minute hand shaft)is excessively effective, the second hand will rotate at an extremelyhigh speed when the timekeeper is set to the correct time by moving thehour and minute hands. Consequently, it will be difiicult to set thetimekeeper to the correct second. Furthermore, since the ratchet wheelrotates at an even higher speed than the second hand, there has been thedanger of causing wear and damage to the teeth of the ratchet wheel.

In order to overcome the above difficulty, it has been the conventionalpractice to resort to such measures as adjusting the friction stop ofthe center wheel shaft and the cannon pinion to operate in a loosemanner, or cautioning the user against reverse rotation during timesetting. In the case of the former measure, however, since the frictionstop is loose, defective rotation of the minute hand often results. Thatis, in spite of the correct operation of the mechanism, the indicationof the minute hand is unstable or the minute hand does not move. As aresult, the value of the timekeeper as a product is greatly lowered.Furthermore, the suitable adjustment of this friction stop is difficultand requires a high degree of skill because of the narrowness of therange of suitability.

It is a general object of the present invention to eliminate theabove-described difiiculties and inconveniences inherent in conventionalelectric timekeepers of this type.

Said object and the other objects of this invention have been attainedby an improvement comprising means to disengage, at the time of timesetting of the timepiece, the said driving pawl and a click forpreventing reverse rotation from the said ratchet wheel and means tolock one part of the said wheel train at the same time.

According to the said improvement, it becomes possible to increase thetolerance of the strength of the friction stop between the cannon pinionand center wheel shaft. The reason for locking one part of the wheeltrain as well as disengaging the driving pawl and a click for preventingreverse rotation from the ratchet wheel is as follows:

Because of the fact that the rotation ratio between the ratchet wheeland one part of the wheel train to be locked at the time setting is verylarge, when minute hand and time hand are to be reversely rotated thereoccurs an apprehension such that the driving pawl and click forpreventing reverse rotation are impaired by the ratchet owing to slightrelaxation of the bearing of the wheel train and mechanical deformationof the means for locking one part of the wheel train.

The nature and details of the invention will be more apparent byreference to the following description taken in conjunction with theaccompanying drawings in which like parts are designated by likereference numerals and characters, and in which:

FIG. 1 is a schematic diagram showing the constructional arrangement ofa conventional electric timekeeper mechanism with which the embodimentof the present invention will be compared;

FIG. 2 is a schematic diagram showing the constructional arrangement ofone embodiment of the present invention;

FIGS. 3, 4, and 5 are schematic views showing the details of theimportant parts of the embodiment shown in FIG. 2;

FIG. 6 is a schematic diagram showing the embodiment of FIG. 2 in adifferent operational state; and

FIGS. 7, 8, and 9 are schematic views for a description of the functionsof the important parts shown in FIG. 6.

Referring to the drawings, the embodiments shown apply to wrist watchesand are depicted in a simplified schematic manner for convenience indescription, but it is to be understood that they have differentconfigurations and arrangements in practical application.

In the conventional system shown in FIG. 1, when the winding button 1 isplaced in the setting state and the time is to be set, one revolution ofthe minute hand M is accompanied by 60 revolutions of the second hand Sand, for example, as high as 1,000 revolutions of the ratchet wheel 15.In ordinary time setting, since the minuted hand is turned onerevolution in a few seconds, the second hand is caused to rotate atabout 600 revolutions per minute (r.p.m.), and the ratchet wheel torotate at a speed as high as 10,000 r.p.m. Consequently, the drivingpawl 17a. and the click 18a for preventing reverse rotation of theratchet wheel 15 are caused to undergo a vibration of 1,000,000 or morecycles per minute.

The parts designated in FIG. 1 by the reference numerals 2-44, 17b, 18band 31 Will be described in conjunction with FIG. 2.

One embodiment of this invention in its normal time indication state, orgo state, is indicated in FIG. 2, in which a winding stem 2 is fixed toand rotates integrally with the winding button 1 and is provided with anannular groove 2a with which ends of a setting lever 3 and a lever 19are engaged. The winding stem 2 is provided also with a sliding pinion2b which is engaged with the winding stem 2 in such a manner as to befreely slidable thereon in the axial direction thereof but to rotatetogether with the wind stem 2. This sliding pinion 2b has an annulargroove 20, in which one end of a clutch lever 4 is engaged. The positionof this clutch lever is controlled by the setting lever 3. This settinglever 3 is pivoted by a shaft 3a which is fixed to a base plate. Thesliding pinion 211 further has a gear 5 fixed thereto to rotateintegrally therewith. During normal time indication or go operation, thegear 5 is separated from the minute wheel 6 of the gear train, asindicated in FIG. 2.

Time regulation and driving power is provided through an oscillatingmember 21 the oscillation of which is maintained electrically. Thisoscillating member 21 is a tuning fork, a tuning bar, or a tuning rod,and drives a spring 17b, provided thereon at a suitable position, inreciprocating motion substantially in the longitudinal direction of thespring 17b. A pawl 17a fixed to the extreme end of the spring 17b isthereby caused to undergo reciprocating motion and drive a ratchet wheel15 in one rotational direction.

The ratchet wheel 15 is prevented from rotating in the reverse directionby a click 18a fixed to the end of a spring 1817. The regulated drivingpower thus imparted by the pawl 17a to the ratchet wheel 15 istransmitted to the minute hand M, hour hand T, and second hand S by wayof the wheel train in the order of: a ratchet wheel pinion 16; an idlerwheel 13 and its pinion 14; a second wheel 11 and its pinion 12; a thirdWheel 9 and its pinion 10; a center wheel 7 and its pinion 8; a minutewheel 6 and its pinion (not shown); an hour wheel (not shown); and anhour hand shaft. The cannon pinion of the minute hand shaft is held byfriction to the center wheel shaft, but this feature is not shown.

The lever 19 which is engaged with the groove 2a of the winding stem 2is rotatable about a pivot 19c and is provided with lugs 19a and 19b,which are so positioned thereon as to be in the engageable vicinity ofsprings 17]) and 18b, respectively, for engagement as will be describedhereinafter. A spring rod 20 is fixed to the lever 19 near its pivot 19cand rotates together with the lever 19. This spring rod 20 is providedat its free end With a tooth 20a which, in the state indicated in FIG.2, is near but not in contact with the second wheel 11.

When the timekeeper is in its normal time indication or go state asshown in FIG. 2, the relative positions of the springs 17b and 18b andthe lugs 19a and 1912 are as indicated in FIG. 3, and the relativepositions of the second wheel 11 and the spring rod 20 and its tooth 20aare as indicated in FIG. 4, which shows a view taken perpendicularly tothe axis of the second wheel, and FIG. 5, which is an enlarged, partialview showing teeth 11a, 11d, of the second wheel 11.

Next, the operation of setting the indicating hands will now bedescribed with reference to FIGS. 6, 7, 8, and 9, wherein thetime-setting state is indicated. When the winding button 1 is pulledoutwardly, the various parts designated by 1, 2, 2b, 3, 4, 5, 19, and 20shift or rotate in the directions indicated by their respective arrowsin FIG. 6. Accordingly, the gear 5 meshes with the minute wheel 6, andthe lugs 19a and 19b engage with the springs 17b and 18b, respectively,and disengage the pawl 17a and the click 18a at the ends of thesesprings from the ratchet wheel 15. Holding pawl 18a is lifted fromengagement with ratchet wheel by lug 1% on lever 19 to allow slightreverse motion of ratchet wheel 15 which may occur when tooth 20a onspring rod 20 enters into one of the spaces between teeth 11a- 11d ofsecond wheel 11. Simultaneously, the second wheel 11 is locked by thespring rod 20 and its tooth 20a, whereby the wheel train of thetimekeeper stops. Then, since the second hand S can be set (stopped) atany position, second setting becomes possible.

The parts of the lugs 19a and 19b which engage with the springs 17b and18b are made amply smooth so that, in the above-described state whereinthe lug 19a is contacting the spring 1711 and keeping the pawl 17a awayfrom the ratchet wheel 15, the oscillating member 21 can oscillate in astable manner.

By tightening the friction stop of the shaft of the center wheel 7 andthe cannon pinion to the extent preventing slippage, setting the handsat any time becomes possible. By pressing the winding button 1 inwardlyafter the hands have been set, the timekeeper system is placed in thestate indicated in FIG. 2, and the time indication or go operation isagain started. In this case, if the oscillation of the oscillatingmember were to be stopped during the setting operation, the timekeepingoperation would not start until the oscillation of the oscillatingmember has reached its normal operating amplitude after the windingbutton has been pressed inwardly. Consequently, it would not be possibleto set the timekeeper to any desired time. In the timekeeper accordingto this invention, however, since the oscillating member is caused tocontinue its oscillation during the setting operation, the timekeepingoperation starts promptly when the winding button is pressed inwardly.

The state of engagement of the lugs 19a and 19b with springs 17b and1812, respectively, when the timekeeper is in the setting state of FIG.6 is indicated diagrammatically in FIG. 7. The engagement of the tooth20a of the spring rod 20 with the fourth wheel 11 is indicated in FIGS.8 and 9.

By the constructional arrangement as described above, the timekeeperembodying the present invention is freed of the afore-describeddisadvantages inherent in conventional timekeepers of this type,wherefore its merchandise value is greatly increased. Moreover, sincefine adjustment of the friction stop mechanism is not necessary, thepresent timekeeper is advantageous from the manufacturing viewpoint.

Although this invention has been described with respect to a particularembodiment thereof, it is not to be so limited as changes andmodifications may be made therein which are within the full intendedscope of the invention, as defined by the appended claims.

What is claimed is:

1. In an electric timekeeper of the type having an oscillating memberwhich is electrically oscillated and provided with a driving pawl whichdrives a ratchet Wheel which, in turn, drives a wheel train for timeindication operation; an improvement comprising a winding stemreciprocably mounted on the timekeeper, means to normally preventretrograde movement of the ratchet Wheel, lever means pivotally mountedon the timekeeper and having one end thereof in engagement with saidwinding stem, lock means on the other end of said lever means, saidwinding stem adapted to be drawn out- 'wardly relative to the timekeeperto pivot said lever means and cause engagement of said lock means with apart of the wheel train to lock the same, and means on said leverintermediate the ends thereof to effect disengagement of the drivingpawl from the ratchet wheel and disengagement from the ratchet wheel ofthe means which normally prevents retrograde movement of the same.

2. In an electric timekeeper as defined in claim 1, wherein said lockmeans on said lever comprises a spring fixed at one end to said lever,and a tooth mounted on the free end of said spring which effects thelock of the part of the wheel train into which the tooth is brought intoengagement.

3. In an electric timekeeper as defined in claim 1, wherein said meansto normally prevent retrograde movemember adapted to freely oscillatewhen the driving pawl is disengaged from the ratchet wheel.

References Cited in the file of this patent UNITED STATES PATENTS2,713,764 St. Vaulry July 26, 1955 2,858,664 I-leimann Nov. 4, 19582,865,163 Ensign Dec. 23, 1958 3,057,147 Hetzel Oct. 9, 1962

1. IN AN ELECTRIC TIMEKEEPER OF THE TYPE HAVING AN OSCILLATING MEMBER WHICH IS ELECTRICALLY OSCILLATED AND PROVIDED WITH A DRIVING PAWL WHICH DRIVES A RATCHET WHEEL WHICH, IN TURN, DRIVES A WHEEL TRAIN FOR TIME INDICATION OPERATION; AN IMPROVEMENT COMPRISING A WINDING STEM RECIPROCABLY MOUNTED ON THE TIMEKEEPER, MEANS TO NORMALLY PREVENT RETROGRADE MOVEMENT OF THE RATCHET WHEEL, LEVER MEANS PIVOTALLY MOUNTED ON THE TIMEKEEPER AND HAVING ONE END THEREOF IN ENGAGEMENT WITH SAID WINDING STEM, LOCK MEANS ON THE OTHER END OF SAID LEVER MEANS, SAID WINDING STEM ADAPTED TO BE DRAWN OUTWARDLY RELATIVE TO THE TIMEKEEPER TO PIVOT SAID LEVER MEANS AND CAUSE ENGAGEMENT OF SAID LOCK MEANS WITH A PART OF THE WHEEL TRAIN TO LOCK THE SAME, AND MEANS ON SAID LEVER INTERMEDIATE THE ENDS THEREOF TO EFFECT DISENGAGEMENT OF THE DRIVING PAWL FROM THE RATCHET WHEEL AND DISENGAGEMENT FROM THE RATCHET WHEEL OF THE MEANS WHICH NORMALLY PREVENTS RETROGRADE MOVEMENT OF THE SAME. 